Therapeutic challenges in ocular delivery of lipid based emulsion

Abstract

In the last decade, lipid based emulsions (LEs) have emerged as a novel tool in ophthalmic drug delivery from the aspect of improved bioavailability (BA). Recent research is focuses on two main approaches for BA improvement i.e., by enhancing the corneal permeability and increasing the retention time of drug on the ocular surface. The LEs have great potential to delivery hydrophobic drug because drug molecules get dissolve in oil globule and main advantage associated are reduced toxic effect and improved self-life of drug molecule. Ophthalmic drug delivery is always an interesting and challenging task for the pharmacologists and formulation scientists due to the unique structure of eye. Development of drug delivery system and its delivery to target receptor of the eye is very difficult for scientists due to the strong defense mechanism of eye. In this review, the focus is to explore key concepts of ophthalmic drug delivery with emphasis on the defense mechanisms, design considerations, and safety assessment of LEs for the ocular drug delivery.

Eco-Friendly Bioemulsifier Production by Mucor circinelloides UCP0001 Isolated from Mangrove Sediments Using Renewable Substrates for Environmental Applications

“…Emulsions are known to be biphasic and thermodynamically unstable systems, so there is a need to incorporate an emulsifying agent [20,21]. The bioemulsifier secreted by M. circinelloides decreased the interfacial tension between the inner (water) and outer (oil) phases causing these phases to mix and the emulsion to remain stable.…”

Advanced Formulation Approaches for Ocular Drug Delivery: State-Of-The-Art and Recent Patents

“…The application of eye drops is characterized by a permeation of the supported drug by a pulsatile mechanism which occurs subsequently to the topical instillation of the drops, with further quick declination of the drug concentration following a kinetic profile corresponding roughly to a first order elimination process. In consequence, to expand the time of contact of the drug, the capacity of permeation and the critical bioavailability of the desired molecule(s), several modifiers are powerful enough to be operated in eye drop formulations, such as cyclodextrins, enhancers of viscosity and of permeability [3,5,15,16].…”

“…Another drawback in the formulation aspect of drugs is related with the reduced time during which the formulation remains inside the ocular globe, determining the success (or not) of a therapeutic. The past decades saw research in the design and experimental analysis of new formulations aimed at increasing the residence time in the ocular tract as well as developing safe and cost-effective systems capable of increasing the permeation through different means [4,5]. To access the anterior segment of the eye, the commonly-used strategies are now concerned much more with enhancers for viscosity and permeation applied to solutions and to other formulations such as emulsions, ointments, and suspensions.…”

Novel Ocular Drug Delivery Systems: An Update on Microemulsions

“…Zwitterionic surfactants such as phospholipids are also applied in MEs. 43,44 The most common used co-surfactants in ocular MEs are ethanol and glycerol. 21,37 Pentanol and hexanol are not frequently used due to their irritation.…”